Sheet glass forming apparatus and method



July 12, 1949. e. w. BATCHELL SHEET GLASS FORMING APPARATUS AND METHOD 3Sheets-Sheet 1 Filed Aug. 28, 1942 fjwowz fiwya @AZC/Z ZZZ fi i fic iCu'komeg July 12, 1949. e. w. BATCHELL SHEET GLASS FORMING APPARATUS ANDMETHOD 3 Sheets-Sheet 5 Filed Aug. 28, 1942 I jncmkoz 9 w? Ema/w tomePatented July 12, 1949 sneer omss ronMrNG APPARATUS AND METHOD George W.Batchell, Toledo, Ohio,assignor"to Toledo Engineering Company, Inc.,Toledo, Ohio,

a corporation of Ohio Application August 28, 1942, Serial No. 456,478

10 Claims.

My invention has for itsobject to provide a means and method for'regulatively controlling the temperature of sheet glass as it is drawnthrough ajleer from the'forebay of a glass furnace by utilizing agaseous composition in the glass passageway through the leer includinghot gases ambient to or gathered in a forebay.

The invention provides a means and method for producing auni'fo'rmcontrolled cooling of the sheet glass after it leaves the forebay tomaintain uniform change in the consistency, particularly of the surfaceglass of the sheet, and thus eliminate wave lines from the glass, whichordinarily appear in the finally formed sheet glass.

Particularly, the invention has for its object to provide pneumaticconduit means, independent of the leer passageway, joining the spaceimmediately adjacent the foreb'ay with the formed glass passageway inthe leer, at a point spaced from the formed glass inlet thereof, andforming, with that part of the leer passageway between said inlet andpoint and with said forebay adjacent space, a, pneumatic circuit,through which hot gases ambient within said forebay adjacent space maybe circulated to temper the formed glass moving through said part of theleer passageway. Further, the invention has for a particularobject' toprovide means forproducing spaced zones of pneumatic pressuredifferentials in said circuit in such relation to said leer passagewaypart andadjacent forebay space as to with-draw hot gases ambient to saidadjacent forebay space and cause pressure equalizing pneumatic flowthereof to said leer passageway part and through the same'in an oppositedirection to that m; which the formed glass is moved throughsaidleer'passageway part.

The invention may be contained in structures of different forms; and, toillustrate a practical application of the invention, I- have selected asheet-glass forming apparatus and method as examples of the variousstructures and steps embodying-the invention and. shall describe theselected apparatus and method hereinafter, it being understood thatcertain features of my invention may be used to advantage Without acorresponding use of other features of the invention and withoutdeparting from the spirit of the invention, aspresented'in' the claims.

The particular structure selected is shown in the accompanying drawings.

This application is;acontinuation in-part of application Ser. No.279,714; filed '-June 17, 1939 and subsequently issued as United StatesPatent No. 2,297,737. I

Fig. 1 of the drawings illustrates a view of a section of the forebayofa'glass furnace,- from which the glass is drawn in sheet form, and atower leer for annealin'gthe sheet glass as it is drawn from the glassof the furnace. Fig. 2 is an enlarged longitudinal section of theforebay of the furnace, and heat reflectors from between which the glassandheated airare'drawn. Fig. 3 is an enlarged transverse section of aWall part of the foreb'ay taken'on the'plan'e'of the line 3-3 indicatedin Fig. 2. 'Fig. 4 illustrates a view of a; section of one side'par't-ofa manifold heatedair inlet also shown in Fig: 1 taken-on a'plane of theline of air'movement.

' The glass furnace l I may beef any well-known type of furnaceformelti'ng glass and directing the refined glass to the 'forebay' I2.The forebay and the furnace may be heated by suitable burners. In theapparatus shown in the drawings, the forebay is heated'by'the' burnersl4, locatedbelow the bottom of the forebay l2. Portions of the productsof combustion of the burners Mare withdrawn through flue '11; as may becontrolled by a gate [8. Also a leer l9 communicates with the forebaythrough a formed glass leer inletlSa to enable the 'sheet glass "to bedrawn from the forebay into-one end ofth e leer.

The forebayis completely covered by acover 20 to form, with the forebayand the-lower or inlet end of the leer l9, achamberZilatin which gasesare gathered'andconfined'for use as hereinafter described. These gasesinclude certain portions of the products of combustion'of burners l4,not withdrawn through the flue I1 and entering the chamber 20a by Way offlue 15; the gases from withinthefurnace ll and' 'the'gases ambient tothe molten glass within the forebay l2. The cover-'20 may be formed, asby steel plate section'smounted on the steelframe and refractory blocksof the furnace andthe'forebay substantially 'as shown in the drawings.

In order to shield-the pool of molten glass in the io'rebay, apair-ofadjustable refractory blocks 2 I- may be tiltablysupp'orted on'sh'oulder'szzand 24 formed of wall parts of the furnace and sustainedby rods 25 and 21 in overhanging relation, with respect to the glass ofthe forebay. The rods 25 and 21 are pivotally connected to suitable lugsthat are formed in the refractory blocks 2| and are provided withthreaded end parts, on which are located suitable nuts 28 and 3|] foradjusting the location of the downwardly extending end flanges 3| and 32of blocks 2| with reference to the surface of the glass in the forebay.

A pair of reflector plates 45 are connected to a pair of pipes or hollowrods 41 that extend through opening 51 in the end walls of the forebayof the furnace. The rods 4! are rotatably supported and connected to theupper edge portions of the reflector plates 45. The lower edge portionsof the reflector plates 45 rest upon rounded edge or beaded portions 43formed on the inner and upper end edges of the blocks 2|. Consequently,as the blocks 2| are adjusted with reference to the surface of theglass, the reflector plates 45 are tilted by angular movements of therods 41. The ends of the rods 41 are supported on hooked ends of therods 50 that extend through sleeves and are provided with threaded endportions, on which are located suitable nuts 52 to adjust the rods withrespect to the sleeves 5|. The sleeves 5| are welded to bushings 53,through which pins 54 extend, the pins being secured to a part of theframe of the forebay for pivotally supporting the rods 50. The angularposition of the rods 50, with respect to the forebay, is adjusted bymeans of the screws 55 that are connected to the sleeves 5|. The screws55 extend through brackets 55 located on one of the beams of the frameof the furnace, and, when rotated, the screws laterally adjust the rods47. Thus, the tubular rods 41 may be adjusted, both vertically andhorizontally, to adjust the reflector plates 45 with respect to thesheet glass as it is initially drawn from the furnace. The upper edgeportions of the reflector plates 45 may be raised with respect to thesheet glass as it is being drawn from the lass of the forebay or may be,if desired, moved toward or away from the surface of the sheet glass. Asthe rods 41 are adjusted, the lower edge portions of the reflectorplates 45 are tilted and slid on the rounded edge portions 48 of theblocks 2|. If desired, the rods 41 may be connected with pipes 59 andcooling air or water directed therethrough. When the rods 4'! arepositioned to adjust the plates 45 in a desired relation, portions ofthe opening 51 may be closed by suitable refractory material.

The reflector plates 45 and blocks 2| not only shield the molten glasspool in the forebay but also divide the chamber 2011 into twosubstantially separate compartments. The lower-most compartment 2%communicates directly with the furnace H and flue l5 and the otheruppermost compartment c communicates directly with the leer I9 throughthe leer inlet l9a. Communication between the compartments 2% and 200 ishad between the approximating edges of the plates 45 between which thedrawn glass sheet moves. As stated the degree of communication may bevaried by the rods 41. Within the compartment 200 and above the upperend edge portions of the blocks 2| and plates 45 are located a pair ofchanneled blocks 34 that are centrally spaced from each other alongmajor D01- tions of their inner edges to form a slot in aligningregistration with the leer inlet |9a and the space between the platesthrough which the glass sheet is drawn. The space 36, between theblocks, forms an elongated dome or curved ceiling part in thecompartment 200. The sheet glass is drawn upwardly from the glass of theforebay, from between the flanges 3| and 32 of the blocks 2|, throughthe dome formed by the space 35, and the slot 35.

The blocks 54 are provided, in their outer lateral surfaces, withchannels, in which are located beams 3! which are connected to the frameof the furnace and its associated parts for supporting the blocks 34 inposition above the forebay i2. A pair of plates 38 (Fig. 2) is solocated as to slidably contact the outer lateral surfaces of the blocks34 and also may be moved so that their lower edges contact the topsurfaces of the blocks 2|. The plates 38 are supported by means ofsuitable brackets 4Q that are secured to the beams 32. Rods 4| areconnected to the plates 33 and extend through sleeves 22 that may besupported on the brackets 48. The upper ends of the rods 4| arethreaded, and suitable nuts 44 are located on the threaded parts of therods 4| to vary the location of the lower edges of the plates 33relative to the blocks 2| for purposes hereinafter described.

As the glass is drawn from the forebay l2, it passes through compartment20b of chamber 200 between the edges or" reflector plates 45, throughcompartment 200 of chamber 26a, the slot 35 and leer inlet l9a into thetower leer 9. The leer I9 is of sumcient height to enable, according tothe drawing rate of the sheet glass, annealing of the glass to eliminateall internal stresses and strains, in advance of cutting the sheet glassinto plates. The lower part of the leer may be heat-insulated bysuitable heatinsulating material to reduce heat absorption byconduction. The upper end of the leer is formed of non-insulated sheetmetal, and heat conduction through the wall of the leer is normal. Theleer may be formed in sections and secured in position by a suitableframe. The leer I9 is provided with a plurality of pairs of spacedrollers ll that have substantially the same surface engagement with thesheet glass. The rollers are interconnected by suitable driving meansfor causing rotation of all rollers at the same rate and to produceuniform rate of movement of all parts of the glass.

The temperature of the interior of the leer I9 is regulated by directingthe gases gathered in the chamber 29a at a pressure and in a quantity tomaintain a relatively slow directed circulation in the leer. Thecomposition of the gases gathered in the chamber 25o, particularly inthe compartment 25c thereof, may be elfectively varied and determined byadjustment of the gate IS, the blocks 2| or the plates 45. An increasedpercentage of the combustion products from the burners it may beobtained by moving the gate l8 toward a closing position of the flue IT.The quantity of admixed furnace and forebay gases may be varied byadjusting the spacing between the upper edges of the plates 45 withreference to the glass sheet being drawn or the spaced relation of theflanges 3| and 32 of the blocks 2| relative to the molten glass surfacewithin the forebay.

Gases from the forebay chamber 20a are drawn by a suction fan 57 of anywell known construction and mode of operation from the forebay of thefurnace through a heat insulated pipe 58 connected to the compartment200 of chamber 25a and directed from the suction fan through the heatinsulated pipe 50 to a manifold ar ea s 6| The;:man-ifo1d -5l"comprisesa ipai -of p pes; Bland 63 terminating atlpoints-spaced,irom theIBQI'jllllGllJQd on opposite sides of the-l kpath-of movementofglassthrough the leer The pipes;

Bland '63 have suitable dampers 64,- for varying the pneumatic flow,therethrough. A,pair of shells 12 and .14 are connected to. the pipes'62 and 53. The shellsare each substantially traps-- zoidal incross-sectional form and have reticulated sides 15 inclined to thevertical for directing gases from the-pipes B2 and E3 downwardlyintotheleer passageway on oppositesides of the sheet glass and producedistributionof; the tern perature. controlling gases throughout the.Width of the leer.

The-pneumatic flow from the comp artment c and through the pipes 58,:60, BI, 62" and 63- may be iurther varieduand adjustedbymovethe-,desired gaseous composition; is-obtained,,in.- thecompartment 20c-and that the suction-pump produces spaced zones ofpressure differentialin the. pneumatic circuitcomp ising pipes 58;;-;60; 5:

manifold l.-,w;pipes 62 and 63; that part-of t plleer passageway,between the points at,which=pipes;-

62 and B3 connect therewith and. the inlet.l9a;-; the. inlet 19a, andcompartment. 20cof,:the fore? bayehamber 20 n. Thezones of pressuredifien;

ential are produced in said pneumaticcircuit so as to-causepneumati flowfrom the high pres.-

sure .zoneto the lower pressure .zone through the leer. passageway partof the pressure zone through- 1 the leer-passagewaypart of the pneumaticircuit in an opposite .direction-to'that in which the.

formed glass sheet is moved by the rollers H.

The forebay gases, introduced through shells l2 and 14, descendby reasonof the-suction of the suction fan 51 or blower and pass through inlet[9a, the slot 35 formed between. the blocks,

34, through the spaces between the blocks 34 and plates and-the sheetglass in compartment 20c and belowrthe edges of the plates 38, throughthe-.1

pipe yfiiietomthe blower and from the blower throughthepipe to theshells 12 and "and into theleer again. Supplementary quantities ofgases-required in the circuit are-drawn into Y thewcompartment 200 frombetween the end flanges 3| and 32 and molten .glass pool in the forebay12 through the edgesof the plates 45 and the sheet glass being drawntherebetween.

The .-upper end of the leer may be provided with a pair of-gates 84located on opposite sides of the sheet glass, that may be opened more orless when it is desired to manipulate the glass for any purpose when itpasses the uppermost of the rollers H. A pair of elastic flexible wipers85 are located so as to contact the surface of the uppermost pair ofrollers 'H for substantially closing the upper end part of the leer and,thus, prevent the escape of any more of the air than is necessary tomaintain the temperature of the air within the upper end of the leer ata proper cooling temperature.

The temperature of the leer is maintained substantially constant withinany horizontal crosssection-al area of the leer, while the temperaturefrom the lower end of the leer progressively decreases but slowly to thepoint at which the hot air inlet shells 12 and 14 are located, Where theglass has been brought below its critical temperature, it then decreasesfrom the shells to the upper end of the leer at a more rapid rate. Thisproduces a more rapid cooling of the glass so that ee t e e aesi d sq afi m,a-i eur remi-- r theil ehvi ei. es mw be om -WI nacehaving-aforebay for receiving molten glass andneans; defining and substantiallyenclosing a spaceiabovethe molten. glass inthe fore-bay. and meansiintheleerfondrawing an elongated continuity ofiglass, formed.in saidspace,through a formedglass inlet of the leer into the leer; the

provision therewith of a communicating means;

independent of the passageway through the leer,

for -.connecting said space; with the interior of the -lee r. .at apoin-t spacedjromthe formed glass inlet t of said leer; and means forproducing. gas, pressure ,diflierentials vin said communicating means and thatpartof the leer passageway extend-ingbetween. the formedglassinlet and the -poi ntofconnection of the communicating meanstherewithwhereby gasirom said iorebay space maybedntroducedinto the leerat .said point and directedthrough the. leer toward the formed glassinlet of the leer. f

2. 'Ina leer fora glass producing furnace having a Iorebay, forreceiving molten glass anda chanfibersubstanti-ally enclosing theforebay, the leerh-aving .a passageway therethrough with an inlet atoneend and meansfor moving formed glass in one direction through the leerinlet and passageway; the combination therewith of cone duit means,independent of the leerpassageway,

havinga passageway, one endof which is con-.

nectedto said chamber and the other to said leer passa gewaygat a pointspacedfrom saidleerinQ let, and iorming with that portion off the leerpassageway between the leer inlet and said point of connection ofisaidconduit means the leer inlet and said chamber, a pneumatic circuit; and

a pneumatic pressure producingmeans connected to said pneu natic circuitfor producing a Zone of low pressure in a part of the circuit wherebygaseous ele nents ambient to the forebay are withdrawn from said chamberand directed into tthe leer passageway bysaid conduit means to flow inheat exchange 'relation withthe formed glass therein toward saidleer'inlet and in a direction opposite to that of the novement of thformed glass through the leer.

,' Br-The combination described in claim 2 having inaddition theretomeans including an adjustable: wall extending across the iorebayenclosingchamber to divide-the chamber into two intercommunicatingcompartments, in one of which is located the forebay molten glass pooland the other of which directly communicates with the conduit means andleer inlet; and means for adjusting said Wall to vary the degree ofintercommunication between said compartments.

4. The combination described in claim 2 having in addition thereto meansfor dividing the forebay chamber into two communicating compartments, inone of which the forebay molten glass pool is located and the other ofwhich is directly connected to the conduit means and leer inlet, saidchamber dividing means comprising a pair of tiltably supportedrefractory blocks disposed in opposed and spaced edge to edge relationand extending laterally from opposite sides of the perimeter of theforebay into the space in said forebay enclosing chamber in proximity toand overhanging the molten glass in said forebay and a pair of tiltablysupported reflector plates disposed in opposed and spaced relation, eachextending toward the other across the space between the proximatingedges of the refractory blocks and having a lateral surface in slidablelapping surf-ace contact with a lateral surface of a refractory block toform an adjustable joint between said refractory block and platesubstantially resistant to the passage of gases therethrough, one of themutually prommating edges of the plates being spaced from the other toform a slot through which communication to both sides of the plates andrefractory blocks may be had.

5. A method of circulating a glass annealing atmosphere within theformed glass passageway of a leer through which formed glass is movedfrom a leer inlet to a leer outlet which includes introducing preheatedgases into the leer at a point spaced along the passageway and path ofmovement of the formed glass therethrough and between the inlet andoutlet of the leer, producing a predetermined pneumatic pressure in thepassageway between the leer inlet and point of introduction of preheatedgases of a lower degree than that prevailing in that part of thepassageway between the outlet and point of introduction of preheatedgases whereby pneumatic -flow of portions of said introduced gases insaid leer passageway occurs in a direction toward said inlet and counterto that in which the formed glass moves through the passageway.

6. The method of producing a glass annealing atmosphere within a leerincluding the steps of introducing gaseous elements prevalent about themolten glass in a forebay of a glass producing furnace withoutsubstantial temperature loss into the leer at a point interjacent theformed glass inlet and outlet of the leer and moving said introducedgaseous elements in a direction toward and through said formed glassinlet.

'7. The method of producing a glass annealing atmosphere within theformed glass passageway of a leer which includes introducing gaseouselements including those ambient to a forebay of a glass producingfurnace, into the leer passageway at a point spaced from the formedglass inlet of the leer; withdrawing atmosphere from that part of theleer passageway which extends between said formed glass inlet and thepoint at which the gaseous elements are introduced into the leerpassageway by producing a low pressure zone in the leer passagewayproximate to said formed glass inlet whereby a portion of saidintroduced gaseous elements directed into said leer passageway will flowfrom said point toward said formed glass inlet of the leer.

8. The method of the preceding claim 7 in which the step of withdrawingatmosphere from that part of the leer passageway between the formedglass inlet and the point at which said gaseous elements are introducedinto the leer passageway is taken coincidentally with the step ofintroducing said gaseous elements into the leer passageway.

9. The method of the preceding claim 7 together with the additional stepof withdrawing the portions of said introduced gaseous elements from theleer passageway and discharging said withdrawn portions of gaseouselements into a forebay of a glass producin furnace whereby saidportions of said gaseous elements may be reheated and mixed with otherportions of gaseous elements ambient to said forebay for subsequentreintroduction to the leer passageway,

10. The method of producing a, glass annealing atmosphere within theformed glass passageway of a tower leer which includes introducingheated gaseous elements into the vertically extending leer passageway ata point spaced above the formed glass inlet thereof; producing apredetermined pneumatic pressure in that part of the leer passagewaybetween said formed glass inlet and said point of gaseous elementsintroduction of a lower degree than the pneumatic pressure prevailing inthe part of the leer passageway between the for-med glass outlet thereofand said point of gaseous elements introduction whereby pneumatic flowof portions of said introduced gaseous elements occurs in a downwarddirection through the leer passageway.

GEORGE W. BATCHELL.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS FOREIGN PATENTS Country Date Australia Oct. 15,1937 Number Number

